[PATCH] D25024: [clang-tidy] Add check for detecting declarations with multiple names

Malcolm Parsons via cfe-commits cfe-commits at lists.llvm.org
Thu Oct 13 08:22:55 PDT 2016


malcolm.parsons added inline comments.


================
Comment at: test/clang-tidy/cppcoreguidelines-one-name-per-declaration.cpp:8
+  {
+    int x = 42, y = 43;
+    // CHECK-MESSAGES: :[[@LINE-1]]:5: warning: Do not declare multiple names per declaration [cppcoreguidelines-one-name-per-declaration]
----------------
omtcyfz wrote:
> malcolm.parsons wrote:
> > The guideline says "Flag non-function arguments with multiple declarators involving declarator operators (e.g., int* p, q;)".
> > 
> > There are no declarator operators in this test, so there should be no warning.
> The guideline says
> 
> > Reason: One-declaration-per line increases readability and avoids mistakes related to the C/C++ grammar. It also leaves room for a more descriptive end-of-line comment.
> 
> > Exception: a function declaration can contain several function argument declarations.
> 
> I'm not sure why what you copied is written in "Enforcement" section, but I do not think that is how it should be handled. I am concerned not only about that specific case and I see no reason to cut off cases already presented in this test.
"mistakes related to the C/C++ grammar" only occur when declarator operators are involved. e.g. in `int* p, q` a reader might incorrectly think that q was a pointer.

I see reasons not to warn about cases like
`for (auto i = c.begin(), e = someExpensiveFn(); i != e; i++)`
`for (int i = 0, j = someExpensiveFn(); i < j; i++);`
because the alternatives increase variable scope, or for
`int x = 42, y = 43;`
because it's not difficult to read.

As we disagree on this, can it be made configurable?


https://reviews.llvm.org/D25024





More information about the cfe-commits mailing list